Frame for filters



Ja n. 22, 1946. o. 'H. 'SCHAAF I FRAME FOR FILTERS Filed Jul 24, 1944' l NvENToR: OLIVER H. Scum/- Armnuevs.

Patented Jan. 22, 1946 FR ME r01; FILTERS Oliver H. Schaaf, ShakenHeighfts, OhioQass ighb'r to Air-Maze CorporatiomCleveland, Ohio, a corporation of Delaware Application July 24, 1944, Serial No. 546,349

2 Claims.

This invention relates to improvements in a frame for an air filter or the like.

An object of the invention is to provide a strong yet cheaply constructed frame of sheet material for an air filter or the like where a frame of polygon shape encircles the filter leaving open front and rear faces for the passage of a gaseous stream. The features of the invention will be apparent from the accompanying. drawing and description, and the essential features thereof will be set forth in the appended claims.

In the drawing: v

Fig. 1 is a perspective view of the device showing one embodiment of my invention;

Fig. 2' is a sectional view of the same taken along the line 2-2 of Fig. 1;

Fig. 3 is a plan view of a blank of sheet material from which my device is constructed;

Figs. 4 and 5 are fragmental sectional views taken along similarly numbered lines of Fig. 1; while Fig. 6 is a perspective view of one end of the formed blank in the finishing corner of the frame.

My invention provides a strong frame for an air filter or the like and one which may be formed from a single blank of sheet material which may be cut out as illustrated in Fig. 3. This blank I has an uninterrupted central strip portion Illa adapted for later bending along the dot-dash lines indicated at II, I2, and I3. Along each side of the central strip portion are 'wide strip portions Illb which are intended to be folded along the lines I 4 to providea frame generally channelform in section as shown at I in Fig. 2. Here the portions Illa provide the web of the channel and the portions IIlb provide the edge flanges at right angles to the web. Referring again to Fig. 3, the side strip portions Iflb are interrupted as shown at I 6 wherever a corner of the frame is to be formed. At these places, a portion of the side strip portions IIlb is entirely removed and slots I 'l are cut extending away, from the cut-out portions in a manner to separate the web and flanges of the channel-shape section at these places. 4

The blank of Fig. 3 is firstfolded along the lines l4 to provide flanges at right angles'to the central or web portion IIIa. Then each of the three corners indicated at I8 (Fig. l)is formed as shown in detail in Fig. 5. The web portion Illa is first folded along the line II so that the angle A is approximately 45 degrees. It is then folded along one of the lines I2, 90 degrees outwardly to formreinforcing ear as indicated at C'. The

angle B is thus about 90 degrees. The web is then foldedalong the line I3 back upon itself approximately 360 degrees, then folded outwardly again on one of the lines I2 so that the angle D is approximately 90 degrees, then folded inwardly again along one of the lines II so that the angle E is approximately 45 degrees. At the fourth corner or finishing corner marked H on Fig. 1, the ends of the blank of Fig. 3 are brought together, and these ends are bent as shown in Figs. 4 and 6, this being made possible by slots I1 analogous to the slots I1 adjacent the previously mentioned openings I6. The end tongues 20 of the blank are then spot welded together as indicated in Fig. 4 so as to hold the frame securely together.

It will be noted that when the blank is folded as above described, the ears 2| of the side strip portions lOb overlap each otheratthe corners of the frame as clearly indicated in Figs. 1, 4, and 5. One of the overlapping portions may be offset by approximately the thickness of the sheet material as indicated at 22 in Fig. 6 so as to provide a flush construction at the-corner. These overlapping ear portions 2| are then secured to- 1 gether either by riveting or as indicated in the drawings by spot welding.

The material within the frame forms no part of the present invention although I have indicated in Fig; 2 an air filter comprising a sheet 23 of woven screen mesh folded in zig-zag form and completely filling the frame. It will be noted that the web portions Illa of the frame completely encircle this filter material leaving the front and rear facesof the frame open for the passage of i a stream or other gas to be filtered.

The above construction provides a cheap but strong frame because each ofthe corners has a diagonal strengthening strip represented by the material lying between the lines II and I2, and in addition, mid way of this diagonal there is an outwardly extending stiffening rib represented by the material lying between the lines I2 and I3 at the corners I8 or represented by the end tongues 20 at the corner I9. These in turn are further strengthened by the overlapping ear portions 2I rigidly secured together and abutting the ends of the strengthening diagonal and the strengthening rib.

Obviously, the frame could be made by four identical sections as would be formed by cutting the blank of Fig. 3'along each of the lines I3. In

this form of construction all of'the corners would look like that shown in Fig. 4, but I prefer the device as shown made out of the single blank of Fi 3.

What I claim is:

1. A generally rectangular frame of sheet material channel-form in section having a web and edge flanges, said web being severed from said flanges at the frame corners, said web at each corner being bent inwardly at approximately forty-five degrees, then outwardly ninety degrees, then inwardly approximately three hundred and sixty degrees, then outwardly ninety degrees, then inwardly approximately forty-five degrees to form the next side of the rectangle, said flanges of adjacent sides overlapping at, each corner, and means there securing said flanges together.

2. A frame for a filter or the like comprising sheet material channel-form in section and bent to form corners of the frame, said channel-form hating a web and two edge flanges, portions of said flanges being entirely cut away at said corners and adjacent portions of said flanges severed from said web, the web of said channel at a zone where said flanges are cut away being bent along a diagonal across the corner, there being excess web material folded substantially at a. right angle from said diagonal, the flanges Of said channel being overlapped at said corner, and means securing said overlapping flanges together.

OLIVER H. SCHAAF. 

